A comparative study on the thermal environment of green roof garden under black veil shading versus bare slab

Green roof utilization is known as a means of urban heat island reduction and building energy saving. Another important function of the green roof is to serve as an alternative recreation and leisure area to the ground, especially in the densely populated urban areas where the open space is limited. Overhead porous polyvinyl chloride black veil is frequently used to improve environmental comfort in Taiwan due to its cheap and easy-construction characteristics. For a better understanding of the micro-thermal environment effect of the planted roof with the application of the black veil, an existing rooftop garden of an office building was studied. Parameters such as ambient dry bulb temperature, wind velocity, globe temperature, wet bulb temperature, were measured. Indices such as mean radiant temperature (MRT) and the wet bulb globe temperature (WBGT) were adopted to describe the thermal sensations perceived by human. Predicting models for estimating thermal environment were also proposed in the end.